CPRE 594 Embedded Systems Research Skills Lecture 11: Tue 4142009 Class Projects, Linux Driver Intro

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CPRE 594Embedded Systems Research SkillsLecture
11 Tue 4/14/2009(Class Projects, Linux Driver
Introduction)
Instructor Dr. Phillip Jones (phjones_at_iastate.edu
) Reconfigurable Computing Laboratory Iowa
State University Ames, Iowa, USA http//www.ece.ia
state.edu
http//class.ece.iastate.edu/cpre594/ and WebCT
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Outline

• Class Project Idea presentations and Feedback
• Introduction to Linux Kernel drivers

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Class Project Ideas

• What did you come up with?

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Class Projects

• Objectives
• Choose fun/cool project to work on
• Make an embedded system do what you want
• Generate a well documented report of what you did
  so others can learn from your experience
• Deliverables
• Short update each week
• What is your progress.
• What interesting things did you come across.
• Final presentation, and documentation turned in
  on day of Final

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Linux Drivers

• The most well know source for learning how to
  develop Linux drivers
• Linux Device Drivers 3rd Edition (Alessandro
  Rubini)
• http//lwn.net/Kernel/LDD3/
• Chapters 1-3 give the basics to get you going.
• Goals
• Write a character device driver for Linux
• Ideally write a driver for the ML507 that
  interfaces to a device
• Example Devices LEDs, DIP switches

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Linux Drivers Overview

• Linux is made up of two major parts
• User Space Users limited to interacting with
  allocated
• virtual address space
• Kernel Space Can access anything!!
• VERY easy to crash your computer if you are not
  careful,
• Well even if you are careful

User Space
Hello World
Socket Programming
Kernel Space
Ethernet
Hardware
PCI
CPU
USB
UART
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Linux Drivers Overview

• Linux Device Drivers Allows user apps to talk to
  devices
• Two types
• Static compiled into the kernel space
• Loadable can be added to the kernel at run-time
• Device driver code has the same power as the
  kernel. It is kernel code.

User Space
Hello World
Socket Programming
Kernel Space
PCI driver
Ethernet
Hardware
PCI
CPU
USB
UART
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Linux Drivers Overview

• Linux Device Drivers Core functions
• Initialize module_init(function 1)
• Read read from a device, Write write to a
  device
• IOCTL part of File Operation (f_op) data
  structure
• Allows userspace applications to access driver
  functions
• Chapter 6, Advanced Character driver
• Clean up module_exit(function 2)

User Space
Hello World
Socket Programming
Kernel Space
PCI driver
Ethernet
Hardware
PCI
CPU
USB
UART
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Assignment

• Create 3-5 side to present you project(s) idea
• Read chapters 1-3 of Linux Device Drivers
• Chapter 6 to learn about ioctl.